The present invention relates to an improved method and device for carrying out measuring operations or interventions in wells and notably in wells drilled through petroliferous zones. These measurings can be achieved within the framework of seismic prospecting operations or to carry out local studies of a well or of the surrounding formations. The method and the device are particularly suitable for carrying out measuring operations in deflected wells, this term referring to wells at least part of which is more or less deflected in relation to the vertical, or more generally any well where the progress of a measuring tool by gravity is difficult.
European Patent EP 296 209 or U.S. Pat. No. 4,945,987 describe a method and a device for carrying out interventions such as measurings in wells which are particularly suitable when these interventions are to be achieved in deflected wells.
The measuring or intervention tool is arranged at the base of a first section of a pipe constituting the end part of a stiff tubing. It is linked to a support frame fitted with removable retaining means through which it can be made interdependent with the end part of the tubing and with a multicontact plug. The retaining means are locked in order to make the support frame interdependent with this section. Through successive additions of sections, the measuring or intervention tool is taken down and pushed along the well until it reaches the upper limit of the zone where the interventions are to be carried out. A socket topped by a weighting bar is introduced by means of a side-entry sub and driven by a current of fluid to a multicontact plug where it is plugged in. Supplementary pipe sections are added in order to push the tool until it reaches the location where the measurings are planned to begin. The tool is fitted with anchoring arms which are opened to immobilize it in the well and several sections of the tubing are taken up in order to move the tool away from its base. The support frame rests then against a thrust at the lower end of the tubing. The measurings can then be carried out either discontinuously by displacing the tool from one location to another after each measuring, while making the tool cling to the wall of the well with the anchoring arms open, or continuously within more or less narrow limits according to the extent of the withdrawal of the tubing.
Displacing the tool can be performed in all cases by a traction on the tubing, and since the latter has to be shortened section by section as it is withdrawn, it becomes obvious that the maximum length on which a continuous move is possible is limited to the length of the utilized sections.
The method according to the invention allows to get free from these limitations.